U.S. patent application number 13/198626 was filed with the patent office on 2011-11-24 for polymer processing additive and molding composition.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Takuya ARASE, Yoshichika KOMIYA, Tsuyoshi MIYAMORI.
Application Number | 20110288221 13/198626 |
Document ID | / |
Family ID | 38625025 |
Filed Date | 2011-11-24 |
United States Patent
Application |
20110288221 |
Kind Code |
A1 |
MIYAMORI; Tsuyoshi ; et
al. |
November 24, 2011 |
POLYMER PROCESSING ADDITIVE AND MOLDING COMPOSITION
Abstract
The invention provides a polymer processing additive which, when
added to a melt-processable resin, is highly effective in improving
the moldability of the resin, and a molding composition containing
the polymer processing additive, among others. This invention is
related to a polymer processing additive comprising a
fluoroelastomer subjected to heat treatment with an alkali metal
inorganic salt or alkaline earth metal inorganic salt added
thereto.
Inventors: |
MIYAMORI; Tsuyoshi; (Osaka,
JP) ; KOMIYA; Yoshichika; (Osaka, JP) ; ARASE;
Takuya; (Osaka, JP) |
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka
JP
|
Family ID: |
38625025 |
Appl. No.: |
13/198626 |
Filed: |
August 4, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12297341 |
Oct 16, 2008 |
|
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PCT/JP2007/058344 |
Apr 17, 2007 |
|
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13198626 |
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Current U.S.
Class: |
524/424 ;
524/429 |
Current CPC
Class: |
C08K 3/10 20130101; C08K
3/105 20180101; C08J 2323/02 20130101; C08J 2427/00 20130101; C08K
3/24 20130101; C08L 27/12 20130101; C08L 23/02 20130101; C08L
2205/06 20130101; C08L 23/02 20130101; C08L 2666/06 20130101; C08J
3/226 20130101 |
Class at
Publication: |
524/424 ;
524/429 |
International
Class: |
C08K 3/26 20060101
C08K003/26; C08K 3/28 20060101 C08K003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2006 |
JP |
2006-114921 |
Claims
1. A method of producing a polymer processing additive comprising
the steps of: adding an alkali metal inorganic salt or alkaline
earth metal inorganic salt to a fluoroelastomer; and subjecting a
mixture of the fluoroelastomer and the alkali metal inorganic salt
or alkaline earth metal inorganic salt to a heat treatment, wherein
the heat treatment is carried out by kneading with heating under
application of a shearing force.
2. The method of producing a polymer processing additive according
to claim 1, wherein the alkali metal inorganic salt or alkaline
earth metal inorganic salt is an alkali metal nitrate.
3. The method of producing a polymer processing additive according
to claim 1, wherein the alkali metal nitrate is potassium
nitrate.
4. The method of producing a polymer processing additive according
to claim 1, wherein the fluoroelastomer is a vinylidene
fluoride/hexafluoropropylene copolymer.
5. The method of producing a polymer processing additive according
to claim 1, wherein the heat treatment is carried out in a
temperature range within which the fluoroelastomer does not undergo
thermal degradation.
6. The method of producing a polymer processing additive according
to claim 1, wherein the heat treatment is carried out in a
temperature range of 120 to 200.degree. C. for 2 to 20 minutes.
7. The method of producing a polymer processing additive according
to claim 1, further comprising the step of adding a partitioning
agent.
8. The method of producing a polymer processing additive according
to claim 1, further comprising the step of grinding the
fluoropolymer or the mixture.
9. A method of producing a masterbatch of a polymer processing
additive, comprising the steps of: preparing a polymer processing
additive by a method of producing the polymer processing additive
according to claim 1; adding the polymer processing additive to a
melt-processable resin (A) to prepare a mixture; and kneading the
mixture.
10. The method of producing a masterbatch of the polymer processing
additive according to claim 9, wherein the content of the
fluoroelastomer in the polymer processing additive is in excess of
0.5% by mass and not higher than 20% by mass of the sum of the mass
of the melt-processable resin (A) and the mass of the
fluoroelastomer.
11. The method of producing a masterbatch of a polymer processing
additive according to claim 9, wherein the melt-processable resin
(A) is a polyolefin resin.
12. A method of producing a masterbatch of a polymer processing
additive, comprising the steps of: adding a fluoroelastomer and an
alkali metal inorganic salt or alkaline earth metal inorganic salt
to a melt-processable resin (A) to prepare a mixture; and kneading
the mixture.
13. A method of producing a product of molding, comprising the
steps of: preparing a polymer processing additive by a method of
producing the polymer processing additive according to claim 1;
preparing a molding composition comprising the polymer processing
additive and a melt-processable resin; and extruding the
composition to obtain the product.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a Rule 53(b) Continuation of application Ser. No.
12/297,341 filed Oct. 16, 2008, which is a 371 of PCT Application
No. PCT/JP2007/058344 filed Apr. 17, 2007, which claims benefit to
Japanese Patent Application No. 2006-114921 filed Apr. 18, 2006.
The above-noted applications are incorporated herein by reference
in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a polymer processing
additive, a molding composition, a masterbatch of a polymer
processing additive and a molded article.
BACKGROUND ART
[0003] A so far proposed method of stabilizing and brightening
melt-processable fluoropolymer resins comprises extruding the
resins in the presence of an alkali metal nitrate (cf. e.g. Patent
Document 1).
[0004] Also known is a method of improving the extrudability of
melt-processable resins which comprises adding a fluoroelastomer as
a polymer processing additive to melt-processable resins. Although
the fluoroelastomer has moldability-improving effects and, thus,
for example it is effective in inhibiting the occurrence of melt
fracture and lowering the extrusion pressure, it is desired that
such effects be further enhanced. [0005] Patent Document 1:
Japanese Kokai Publication H10-292054
DISCLOSURE OF INVENTION
Problems which the Invention is to Solve
[0006] In view of the above-discussed state of the art, it is an
object of the present invention to provide a polymer processing
additive which, when added to melt-processable resins, is highly
effective in bringing about improvements in moldability as well as
a molding composition comprising the polymer processing
additive.
Means for Solving the Problems
[0007] The present invention provides a polymer processing additive
comprising a fluoroelastomer subjected to heat treatment with an
alkali metal inorganic salt or alkaline earth metal inorganic salt
added thereto.
[0008] The present invention provides a molding composition
comprising a melt-processable resin and a polymer processing
additive, wherein the polymer processing additive is the polymer
processing additive mentioned above.
[0009] The present invention provides a masterbatch of a polymer
processing additive comprising a melt-processable resin (A) and the
polymer processing additive mentioned above.
[0010] The present invention provides a molded article being the
product of molding of the molding composition mentioned above.
[0011] In the following, the present invention is described in
detail.
[0012] The fluoroelastomer in the polymer processing additive of
the invention is not particularly restricted but may be any one
known in the art provided that it is a noncrystalline fluoropolymer
containing carbon atom-bound fluorine atoms and having rubber
elasticity.
[0013] The fluoroelastomer generally has a first monomer-derived
comonomer unit content of 30 to 80% by mass.
[0014] The term "first monomer" as used herein means a monomer from
which those comonomer units accounting for a major mass fraction
among all the comonomer units in the molecular structure of the
fluoroelastomer are derived.
[0015] The comonomer unit so referred to herein is a moiety in the
molecular structure of the fluoroelastomer and denotes a moiety
derived from the corresponding monomer. For example, the vinylidene
fluoride [VDF] unit is a moiety of the molecular structure of a
VDF-based copolymer and is a moiety derived from VDF and is
represented by --(CH.sub.2--CF.sub.2)--. "All the comonomer units"
so referred to herein include all monomer-derived moieties in the
molecular structure of the fluoroelastomer.
[0016] The comonomer unit contents can be determined by
.sup.19F-NMR measurements.
[0017] In the practice of the invention, the fluoroelastomer may be
either one in which the comonomer units other than those derived
from the first monomer are derived from only one monomer
copolymerizable with the first monomer or one in which such
comonomer units are derived from two or more monomers
copolymerizable with the first monomer.
[0018] The monomer copolymerizable with the first monomer may be,
for example, a fluoroolefin, a fluorovinyl ether or a hydrocarbon
olefin.
[0019] The fluoroolefin is not particularly restricted but
includes, for example, VDF, tetrafluoroethylene [TFE],
hexafluoropropylene [HFP], 1,2,3,3,3-pentafluoropropene,
chlorotrifluoroethylene [CTFE] and vinyl fluoride [VF].
[0020] The fluorovinyl ether includes, among others,
perfluoro(vinyl ether) species.
[0021] The perfluoro(vinyl ether) includes, among others,
perfluoro(alkyl vinyl ether) [PAVE] species.
[0022] Preferred as the PAVE are those having a perfluoroalkyl
group containing 1 to 6 carbon atoms, such as perfluoro(methyl
vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE] and
perfluoro(propyl vinyl ether) [PPVE].
[0023] When the fluoroelastomer has PAVE units, the PAVE unit
content is preferably 20 to 40% by mass based on all the comonomer
units.
[0024] The hydrocarbon olefin is not particularly restricted but
includes, among others, ethylene and propene; propene is preferred,
however.
[0025] When the fluoroelastomer has hydrocarbon olefin units, the
hydrocarbon olefin unit content is preferably 4 to 20% by mass
based on all the comonomer units.
[0026] As the fluoroelastomer, there may be mentioned, for example,
TFE/perfluoro(vinyl ether)-based copolymers, VDF/HFP-based
copolymers, VDF/CTFE-based copolymers, VDF/TFE copolymers,
VDF/HFP/TFE-based copolymers, VDF/CTFE/TFE-based copolymers,
TFE/propylene-based copolymers, TFE/propylene/VDF-based copolymers,
ethylene/HFP-based copolymers and like fluorocopolymers. Among
them, VDF-based copolymers where the first monomer is VDF or
TFE-based copolymers where the first monomer is TFE are preferred,
and such VDF-based copolymers are more preferred.
[0027] More preferred as the fluoroelastomer are, among others,
VDF/HFP copolymers and VDF/TFE/HFP copolymers; still more preferred
are VDF/HFP copolymers.
[0028] The polymer processing additive of the invention may
comprise one fluoroelastomer species or two or more fluoroelastomer
species.
[0029] The fluoroelastomer generally has a number average molecular
weight [Mn] of 13000 to 470000.
[0030] A preferred lower limit to the above Mn is 15000, and a
preferred upper limit thereto is 320000.
[0031] The number average molecular weight, so referred to herein,
is measured by carrying out gel permeation chromatography, as
described later herein.
[0032] The polymer processing additive of the invention is prepared
by using a fluoroelastomer subjected, with an alkali metal
inorganic salt or an alkaline earth metal inorganic salt
(hereinafter sometimes referred to as "specific metal inorganic
salt") added thereto, to heat treatment.
[0033] The fluoroelastomer can be prepared in the conventional
manner known in the art except for the addition of a specific metal
inorganic salt and the subsequent heat treatment. As the steps
other than the heat treatment, there may be mentioned, among
others, the steps of polymerization of the above-mentioned
fluoromonomer or fluoromonomers, optionally together with a
fluorine-free monomer or monomers, optional post-treatment of the
aqueous fluoroelastomer dispersion obtained (e.g. dilution,
concentration, purification), coagulation of the aqueous
fluoroelastomer dispersion or the dispersion after post-treatment,
drying of the fluoroelastomer coagulum (sometimes referred to also
as "crumbs") obtained in the step of coagulation, and grinding of
the fluoroelastomer obtained after drying. The conditions in each
step can be properly selected according to the materials to be
used, the desired fluoroelastomer species and the amount thereof,
among others.
[0034] As the metal constituting the specific metal inorganic salt,
there may be mentioned, for example, magnesium and, further,
lithium, sodium, potassium, calcium, barium and so forth.
[0035] The specific metal inorganic salt is not particularly
restricted but preferably is an alkali metal nitrate or an alkaline
earth metal nitrate; alkali metal nitrates are more preferred among
others.
[0036] As the alkali metal nitrate, there may be mentioned, for
example, sodium nitrate and potassium nitrate and, among them,
potassium nitrate is preferred. The alkaline earth metal nitrate
is, for example, magnesium nitrate.
[0037] It is generally preferred that the specific metal inorganic
salt be added on the occasion of heat treatment in an amount
corresponding to 20 to 2000 ppm by mass of the fluoroelastomer.
[0038] A preferred lower limit to the addition level is an amount
corresponding to 100 ppm of the fluoroelastomer, and a preferred
upper limit thereto is an amount corresponding to 1000 ppm of the
fluoroelastomer.
[0039] The specific metal inorganic salt is preferably added in the
form of an aqueous solution from the uniform dispersion viewpoint,
although it may be added in the form of a solid as such.
[0040] The addition of the specific metal inorganic salt may be
carried out in a manner such that the specific metal inorganic salt
coexists with the fluoroelastomer at the point of time when the
heat treatment is carried out according to the invention. When the
specific metal inorganic salt is an electrolyte, it is considered
preferable that the addition be made after polymerization of the
fluoromonomer(s), optionally together with a fluorine-free monomer
in the process of preparing the fluoroelastomer. However, (1) the
salt may be added to the aqueous fluoroelastomer dispersion
obtained by the polymerization, (2) the addition may be made on the
occasion of such a post-treatment as dilution, concentration or
purification of the aqueous fluoroelastomer dispersion, which is
carried out according to need, (3) the addition may be made on the
occasion of coagulation of the aqueous fluoroelastomer dispersion
or the dispersion after such post-treatment as mentioned above, (4)
the addition may be made on the occasion of drying the coagulum
obtained by the above coagulation, (5) the addition may be made in
the manner of incorporation by kneading into the fluoroelastomer
after drying, or (6) the addition may be made on the occasion of
preparing a masterbatch of the polymer processing additive, which
is to be described later herein, using the fluoroelastomer after
drying.
[0041] In the practice of the invention, the addition of the
specific metal inorganic salt is preferably made on the occasion of
drying (4) or kneading (5), or on the occasion of masterbatch of
the polymer processing additive preparation (6) and, from the
sufficient heat treatment viewpoint, it is preferably made on the
occasion of drying (4).
[0042] In the case of addition on the occasion (4), the addition is
preferably carried out continuously in the course of drying of the
fluoroelastomer coagulum, which is to be described later herein,
for attaining uniform dispersion of the specific metal inorganic
salt.
[0043] The heat treatment according to the invention may be carried
out on any of the occasions (1) to (6) mentioned above either
simultaneously with or after the addition of the specific metal
inorganic salt. From the procedural convenience viewpoint, however,
it is preferably carried out on the occasion of drying (4) or
masterbatch of the polymer processing additive preparation (6).
[0044] In the case of carrying out the heat treatment on the
occasion (5) mentioned above, it is preferred that the elastomer
after drying be ground using a grinding machine and, after addition
of the inorganic salt, the mixture is melt-kneaded.
[0045] In the masterbatch of the polymer processing additive
preparation (6) mentioned above, it is preferred, from the improved
fluoroelastomer dispersibility viewpoint, that the specific metal
inorganic salt be added to the fluoroelastomer in a form
preliminarily ground after drying and the mixture be melt-kneaded
with a melt-processable resin, namely the host polymer.
[0046] The ground elastomer preferably has an average particle
diameter of 5 .mu.m to 5 mm. A more preferred lower limit to the
above average particle diameter is 200 .mu.m, and a more preferred
upper limit thereto is 3 mm.
[0047] The average particle diameter as reported herein is the
value measured in accordance with JIS K 6891-1995. The average
particle diameter (d50) is determined as follows: based on the
particle diameter distribution measurement results obtained
according to JIS K 6891-1995, the cumulative particle weight
percentage (%) data obtained by classification are plotted against
the sieve mesh opening (.mu.m) on a logarithmic graph paper sheet,
and the particle diameter at the cumulative percentage of 50% is
read or, alternatively, a straight line is determined by the least
squares method and the 50% particle diameter is calculated.
[0048] The heat treatment according to the invention is carried out
by kneading with heating under application of a shearing.
force.
[0049] It is expected that the application of a shearing force in
the above heat treatment makes it possible for the specific metal
inorganic salt to be incorporated adequately into the
fluoroelastomer and thus homogeneously dispersed in the
fluoroelastomer and, when the elastomer treated is added to a
melt-processable resin, a polymer processing additive excellent in
dispersibility of the fluoroelastomer in the melt-processable resin
can be obtained and the moldability-improving effect can be further
enhanced.
[0050] The shearing force resulting from kneading can be exerted,
for example, by feeding to an extruder, for example a twin-screw
extruder, and extruding.
[0051] When the drying step after coagulation of the
fluoroelastomer is carried out using an extruder, the procedure for
applying heat and a shearing force can be carried out on the
occasion of kneading of the fluoroelastomer in that extruder while
adding the specific metal inorganic salt, or that procedure can
also be carried out on the occasion of kneading of the
fluoroelastomer in an extruder, such as a twin-screw extruder, for
the masterbatch preparation to be described later herein, by
kneading the specific metal inorganic salt with the elastomer.
[0052] The conditions in each procedure can be properly selected
according to the composition and amount of the heat treatment
target dispersion or coagulum and other factors.
[0053] Generally, the temperature for the above heat treatment may
be within a temperature range within which the fluoroelastomer will
not undergo thermal degradation; preferably, it is 120 to
200.degree. C. A more preferred lower limit to the above
temperature is 140.degree. C., and a more preferred upper limit
thereto is 180.degree. C.
[0054] The heat treatment is carried out generally for 2 to 20
minutes, preferably for 5 to 10 minutes.
[0055] The polymer processing additive of the invention may further
contain, in addition to the fluoroelastomer after the
above-mentioned heat treatment, an additive or additives, for
example an partitioning agent. When an partitioning agent is added,
the particles resulting from grinding of the fluoroelastomer can be
prevented from caking and, when the polymer processing additive of
the invention is added to a melt-processable resin, the
dispersibility of the fluoroelastomer particles can be further
improved.
[0056] The partitioning agent is not particularly restricted but
includes, among others, plasticizers such as dioctyl phthalate and
diglycidyl phthalate; fillers such as talc, graphite and silica;
colorants such as titanium oxide, iron oxide and molybdenum oxide;
acid acceptors such as magnesium oxide, calcium oxide and lead
oxide; heat stabilizers such as calcium stearate and magnesium
stearate; and surfactants such as polyethylene glycol and
polycaprolactone.
[0057] Fillers are preferred as the partitioning agent, and talc,
calcium carbonate and the like are more preferred.
[0058] The amount of the partitioning agent in the polymer
processing additive of the invention can be properly selected
according to the fluoroelastomer species and the amount thereof and
other factors but, generally, the amount is 1 to 15 parts by mass
per 100 parts by mass of the fluoroelastomer and the amount is
preferably as small as possible.
[0059] The amount of the partitioning agent to obtain the minimum
required effect is more preferably not smaller than 2 parts by
mass, still more preferably not smaller than 4 parts by mass, and
more preferably not greater than 10 parts by mass, per 100 parts by
mass of the fluoroelastomer.
[0060] The polymer processing additive of the invention can be used
by adding a melt-processable resin.
[0061] The polymer processing additive of the invention is
excellent in dispersibility in melt-processable resins and, for
example on the occasion of molding of a melt-processable resin, it
can be dispersed in the form of fluoroelastomer particles having an
average particle diameter of about 2 .mu.m in the melt-processable
resin even if the polymer processing additive is in a roughly
ground form with a size of 1 mm to 5 mm, whereas when it is in a
finely ground form with a size not smaller than 10 .mu.m but
smaller than 1000 .mu.m, it can be dispersed in the
melt-processable resin as polymer processing additive particles
with an average particle diameter of about 1 .mu.m. Hence, the
latter finely ground form is preferred.
[0062] On the other hand, the fluoroelastomer having no experience
of the above-mentioned heat treatment, even when used in the form
of a finely divided material, may sometimes allow dispersion, in
the melt-processable resin, of fluoroelastomer particles with an
average particle diameter of about 3 to 10 .mu.m according to the
extruder capacity.
[0063] Therefore, it is thought that the polymer processing
additive of the invention can readily produce the
moldability-improving effect intrinsic in the fluoroelastomer to a
sufficient extent as compared with the conventional polymer
processing additive.
[0064] The polymer processing additive of the invention, which
comprises the fluoroelastomer after experience, together with an
alkali metal salt or alkaline earth metal salt added thereto, of
the above-mentioned heat treatment, is superior in the effect of
improving the moldability of melt-processable resins as compared
with the conventional polymer processing additives and, in the case
of extrusion processing, for instance, it allows the extrusion
pressure to be lowered and melt fracture to disappear in a short
period of time as compared with the fluoroelastomer having the same
copolymer composition but containing no such inorganic salt as
mentioned above.
[0065] Therefore, the polymer processing additive of the invention
is very useful as a material for use in molding compositions and in
masterbatches of polymer processing additives.
[0066] The molding composition of the invention comprises a
melt-processable resin and the above-mentioned polymer processing
additive of the invention.
[0067] The term "melt-processable resin" as used herein means a
polymer for which the melt flow can be measured at temperatures
higher than the crystallization temperature in accordance with ASTM
D-1238 and D-2116.
[0068] The melt-processable resin is not particularly restricted
but is preferably a fluorine-free resin. Thus, for example, it
includes, among others, polyolefin resins such as polyethylene and
polypropylene; polyamide [PA] resins such as nylon 6, nylon 11,
nylon 12, nylon 46, nylon 66, nylon 610, nylon 612 and nylon MXD6;
polyesters such as polyethylene terephthalate [PET], polybutylene
terephthalate [PBT], polyarylates, aromatic polyesters (including
liquid crystal polyesters) and polycarbonates [PCs]; polyacetal
[POM] resins; polyether resins such as polyphenylene oxide [PPO],
modified polyphenylene ethers and polyetheretherketones [PEEKs];
polyamideimide [PAI] resins such as polyaminobismaleimide;
polysulfone type resins such as polysulfones [PSFs] and
polyethersulfones [PESs]; vinyl polymers such as ABS resins and
poly-4-methylpentene-1 (TPX resins); and, further, polyphenylene
sulfide [PPS], polyketonesulfides, polyetherimides and polyimides
[PIs]. The above-mentioned nylon MXD6 is a crystalline
polycondensate obtained from metaxylenediamine [MXD] and adipic
acid.
[0069] Among them, polyolefin resins and PA resins are preferred as
the melt-processable resin; polyolefin resins are more
preferred.
[0070] The melt-processable resin in the molding composition is
preferably a thermoplastic resin in view of its ready
moldability.
[0071] In the molding composition of the invention, the
melt-processable resin may comprise one single component or a
combination of two or more components.
[0072] The melt-processable resin is preferably one having a
melt-processing temperature of 100 to 350.degree. C. The
melt-processable resin may have crystallinity or no
crystallinity.
[0073] In the case of its having crystallinity, the
melt-processable resin preferably has a melting point of 80 to
300.degree. C., more preferably a melting point of 100 to
200.degree. C.
[0074] In the case of its having no crystallinity, the
melt-processable resin is preferably almost equivalent in
processing temperature to the crystalline melt-processable resin
for which the melting point range is given above.
[0075] The melt-processable resin can be composed by those methods
well known as in the past, among others, according to the type
thereof.
[0076] The melt-processable resin may be in the form of a powder,
granules or pellets, for instance. Pellets are preferred since they
make it possible to efficiently melt the melt-processable resin in
the molding composition obtained and disperse the polymer
processing additive therein.
[0077] In the molding composition of the invention, the
heat-treated fluoroelastomer contained in the polymer processing
additive preferably amounts to 0.001 to 5% by mass relative to the
sum of the total mass of the melt-processable resin and the mass of
the fluoroelastomer.
[0078] The fluoroelastomer more preferably amounts to not less than
0.01% by mass and not more than 0.5% by mass relative to the sum of
the total mass of the melt-processable resin and the mass of the
fluoroelastomer.
[0079] The molding composition may be one prepared by adding the
polymer processing additive of the invention as such to the
melt-processing resin or one prepared by adding the polymer
processing additive in the form of a masterbatch of the polymer
processing additive, which is to be described later herein, to the
melt-processable resin.
[0080] The molding composition of the invention may comprise,
together with the above-mentioned polymer processing additive and
melt-processable resin, one or more other components incorporated
therein according to need.
[0081] The other components are not particularly restricted but
include, among others, reinforcing agents such as glass fibers and
glass powders; stabilizers such as minerals and flakes; lubricants
such as silicone oils and molybdenum disulfide; pigments;
electroconductive materials such as carbon black; impact resistance
improving agents such as rubbers; and other additives listed on the
positive list made up as a self-regulatory standard by the Japan
Hygienic Olefin and Styrene Plastics Association.
[0082] The masterbatch of the polymer processing additive of the
invention comprises a melt-processable resin (A) and the polymer
processing additive of the invention. The masterbatch of the
polymer processing additive of the invention can be suitably used
as a polymer processing additive on the occasion of molding the
melt-processable resin (A).
[0083] The masterbatch of the polymer processing additive of the
invention contains the fluoroelastomer uniformly dispersed in the
melt-processable resin (A) and, therefore, when added to a
melt-processable resin on the occasion of molding thereof, can
improve the moldability thereof, reducing the extrusion torque or
extrusion pressure, for instance.
[0084] As the melt-processable resin (A), there may be mentioned
the same melt-processable resins as enumerated above. Among them,
polyolefin resins are preferred, and polyethylene is more
preferred.
[0085] Generally, the polymer processing additive particles in the
masterbatch of the polymer processing additive of the invention
preferably have an average particle diameter of 0.01 to 10 .mu.m,
more preferably 0.1 to 2 .mu.m.
[0086] It does not matter whether the masterbatch of the polymer
processing additive of the invention is in the form of a powder,
granules, pellets or the like. Pellets prepared by melt-kneading
are preferred, however, in view of the fact that the heat-treated
fluoroelastomer is maintained in a finely dispersed state in the
melt-processable resin (A).
[0087] In the masterbatch of the polymer processing additive of the
invention, the fluoroelastomer preferably amounts to a proportion
exceeding 0.5% by mass but not higher than 20% by mass based on the
sum of the mass of the melt-processable resin (A) and the mass of
the fluoroelastomer since the melt molding to be described later
herein is then facilitated.
[0088] A more preferred lower limit to the content of the
fluoroelastomer is 1% by mass of the above-mentioned sum of the
masses, a still more preferred lower limit is 2% by mass, and a
more preferred upper limit is 10% by mass.
[0089] The masterbatch of the polymer processing additive of the
invention may comprise, together with the above-mentioned polymer
processing additive and melt-processable resin (A), one or more
other components incorporated therein according to need.
[0090] The other components are not particularly restricted but
there may be mentioned, for example, those enumerated above
referring to the molding composition of the invention.
[0091] While the masterbatch of the polymer processing additive of
the invention can also be obtained by kneading, at a temperature of
100 to 350.degree. C., a mixture prepared by adding the polymer
processing additive-constituting fluoroelastomer and the
above-mentioned inorganic salt, optionally together with an
partitioning agent and/or the like, to the melt-processable resin
(A), the one obtained by kneading a mixture prepared by adding the
polymer processing additive prepared in advance to the
melt-processable resin (A) at such a temperature as mentioned above
is preferred from the viewpoint of the dispersibility of the
fluoroelastomer.
[0092] The above-mentioned masterbatch of the polymer processing
additive is readily dispersible in melt-processable resins and,
therefore, the molded/processed articles obtained are homogeneous
and such appearance defects as gel-like lumps hardly appear in cast
films or blown films.
[0093] The molded article of the invention is a product of molding
of the above-mentioned molding composition of the invention.
[0094] The molding may be carried out by preliminarily preparing
the molding composition of the invention and then feeding the same
to a molding machine for melting and extrusion, for instance, or by
feeding the above-mentioned polymer processing additive and a
melt-processable resin simultaneously to a molding machine for
melting and extrusion, for instance, or by simultaneously feeding
the above-mentioned masterbatch of the polymer processing additive
and melt-processable resin to a molding machine for melting and
extrusion, for instance.
[0095] The method of molding of the molding composition is not
particularly restricted but there may be mentioned, for example,
extrusion, injection molding and blow molding. For effective
utilization of the moldability mentioned above, however, extrusion
is preferred among others.
[0096] Various conditions in carrying out the molding are not
particularly restricted but can be properly selected according to
the composition and amount of the molding composition to be used,
the shape and size of the desired molded articles and other
factors.
[0097] The molding temperature is generally at a level not lower
than the melting point of the melt-processable resin in the molding
composition but lower than the temperature which is the lower of
the respective decomposition temperatures of the polymer processing
additive and melt-processable resin and is within the range of 100
to 350.degree. C.
[0098] In the case of extrusion, the molding temperature is
sometimes referred to as "extrusion temperature".
[0099] The molded article of the invention may have various shapes,
for example sheet-like, film-like, rod-like, pipe-like and fibrous
shapes.
[0100] The field of application of the molded article is not
particularly restricted but, according to the melt-processable
resin species, the molded article is suitably used, for example, in
the fields where mechanical properties and dynamical properties
and/or surface properties, in the main, are strongly demanded.
[0101] As the uses of the molded article, there may be mentioned,
for example, various films, bags, covering materials, containers
for drinks and like eating/drinking utensils, cables, pipes,
fibers, bottles, gasoline tanks and other various industrial
moldings.
EFFECTS OF THE INVENTION
[0102] The polymer processing additive and masterbatch of the
polymer processing additive of the invention, which have the
respective constitutions described hereinabove, are more effective
in reducing the extrusion pressure, inhibiting melt fracture and
thus improving the moldability as compared with the conventional
ones. The molding composition of the invention, which comprises the
polymer processing additive mentioned above, is excellent in
moldability, and the molded article of the invention, which is the
product of molding of the molding composition mentioned above, is
excellent in mechanical properties and other dynamic
properties.
BEST MODES FOR CARRYING OUT THE INVENTION
[0103] The following examples and comparative examples illustrate
the present invention in further detail. These examples and
comparative examples are, however, by no means limitative of the
scope of the invention.
[0104] The amounts given in each example and each comparative
example are on the mass basis unless otherwise specified.
[0105] The measured values described in each example and each
comparative example are values determined by the following
respective methods.
[0106] 1. Copolymer Composition
[0107] Measurements were made using a .sup.19F-NMR spectrometer
(Bruker model AC300P).
[0108] 2. Number Average Molecular Weight
[0109] Measurements were made by carrying out gel permeation
chromatography under the following conditions:
Measuring apparatus: LS-8000 (product of TOSOH Corporation) Column:
TSK guard column HXL-H (TSK gel G4000HXL, TSK gel G3000HXL, TSK gel
GMHXL-H)
[0110] Detector: differential refractometer
[0111] Developing solvent: tetrahydrofuran
[0112] Measurement temperature: 35.degree. C.
[0113] Sample concentration: 5 g/L
[0114] Standard samples: various monodisperse polystyrene
species=1.14 (Max), TSK standard POLYSTYRENEs, products of TOSOH
Corp.
[0115] 3. Extrusion Pressure
[0116] Measurements were made using a pressure measuring apparatus
(product of Dynisco Japan, Ltd.) under the extrusion conditions
mentioned later herein.
[0117] 4. Melt Fracture
[0118] The incidence of melt fracture was determined by the
following procedure.
[0119] At each observation time, the blown film was sampled and
converted to a flat film by incision along a line.
[0120] The state of the occurrence of melt fracture all over in the
radial direction in blowing was regarded as 100% width, the width
of the occurrence of melt fracture was measured at each measurement
time using a tape measure and the incidence was calculated as the
ratio to the 100% width.
[0121] The time at which the incidence of melt fracture for the
first time became 0% was recorded as the time of complete
disappearance of melt fracture.
Example 1
[0122] A fluoroelastomer [FKM] (vinylidene fluoride
[VDF]/hexafluoropropylene [HFP] copolymer, copolymer composition
(mole ratio): VDF/HFP=79/21, number average molecular weight 83000)
was prepared by polymerization and the crumbs obtained after
coagulation was transferred to a twin-screw extruder (TEM75;
product of TOSHIBA MACHINE Co.) and dried by extrusion under the
following conditions.
(Extrusion Conditions)
[0123] (1) Temperatures: cylinder temperature 150 to 180.degree.
C., die temperature 150.degree. C. (2) Number of screw revolutions:
100 rpm
[0124] During this drying, a 20% aqueous solution of KNO.sub.3 was
fed to the extruder and an FKM/KNO.sub.3 composition was obtained.
The KNO.sub.3 treatment concentration was equal to an amount
corresponding to 400 ppm of the mass of FKM after drying.
[0125] The FKM/KNO.sub.3 composition obtained was ground on a
cutter type grinding mill (Rapid R1528, product of KAWATA MFG Co.)
to give a roughly ground FKM-based composition with an average
particle diameter of 1 to 3 mm.
[0126] A 40-g portion of the roughly ground FKM-based composition
was covered with 4 g of talc to give a polymer processing additive.
The polymer processing additive obtained was blended, by tumbling,
with 1956 g of low-density polyethylene [LDPE] (LDPE SUMIKATHENE
G201, MFR=2, product of SUMITOMO POLYETHYLENE) so that the FKM
might amount to 2% by mass of the resin; and the mixture was fed to
a twin-screw extruder (KZW15TW-60MG, product of TECHNOVEL CORP.) to
give a masterbatch of the polymer processing additive.
(Extrusion Conditions)
[0127] (1) Temperatures: 180 to 210.degree. C., die temperature
210.degree. C. (2) Number of screw rotations: 600 rpm
(3) L/D: 60
[0128] The fluoroelastomer was found dispersed as particles with an
average particle diameter of 1 to 2 .mu.m in the masterbatch of the
polymer processing additive (cf. FIG. 1).
[0129] Further, the masterbatch of the polymer processing additive
was evaluated for extrudability in blown film manufacture according
to the following procedure.
[0130] 1. A single-screw extruder (Tanabe Plastics Machinery model
VS30-26 extruder, L/D: 26, screw diameter: 30 mm) equipped with an
tubular die (product of Tanabe Plastics Machinery; die diameter 60
mm, die gap 0.5 mm) was fed with metallocene-catalyzed linear
low-density polyethylene [metallocene LLDPE] (product name: Evolue
SP2520, product of PRIME POLYMER Co.) for an about 1 hour of
continuous extrusion under the conditions specified below and it
was confirmed that the extrusion pressure was stably about 38 MPa,
without changes, and the blown film extruded showed the occurrence
of melt fracture all over the surface thereof.
(Extrusion Conditions)
[0131] (1) Temperatures: cylinder temperature C1 (120.degree. C.),
C2 (130.degree. C.), C3 (130.degree. C.), C4 (140.degree. C.), die
temperature (150.degree. C.) (2) Number of screw revolutions: 50
rpm (3) Take-off speed: 5 m/minute
[0132] 2. Then, the above-mentioned metallocene LLDPE and the
masterbatch of the polymer processing additive were weighed so that
the amount of FKM after mixing might amount to 500 ppm; they were
placed in a polyethylene bag and mixed up by tumbling. The molding
composition obtained was fed to the hopper of the above-mentioned
extruder. Immediately after feeding of the molding composition, the
observation of changes in extrusion pressure was started.
[0133] The time required for the metallocene LLDPE remaining in the
extruder to be discharged was about 5 minutes after the start of
the feeding mentioned above and, after the lapse of about 5 minutes
following the above feeding, the extrusion pressure began to lower
and the incidence of melt fracture began to decrease. After 20
minutes following the start of the feeding, melt fracture was no
longer observed at all and the extrusion pressure dropped from 38.0
MPa to 36.0 MPa.
[0134] The extrusion pressure observation was carried out
continuously for 40 minutes.
[0135] The melt fracture measurement results are shown in FIG.
2.
[0136] After the above extrudability evaluation, the above extruder
was purged with a mixture of the above-mentioned metallocene LLDPE
and 1% by mass of talc and then purged with the metallocene LLDPE
fed alone. In each purging run, the extrusion was extruded
continuously for about 4 hours under the same conditions as in the
extrudability evaluation and, after confirmation of the extrusion
pressure to the original level, the purging run was finished.
Example 2
[0137] To a fluoroelastomer [FKM] (vinylidene fluoride
[VDF]/hexafluoropropylene [HFP] copolymer, copolymer composition
(mole ratio): VDF/HFP=78/22, number average molecular weight 64000)
was added a 20% by mass aqueous solution of KNO.sub.3 in an amount
such that the treatment concentration might correspond to 250 ppm
of FKM, and the mixture was subjected to heat treatment in the
manner of extrusion/drying under the same conditions as in Example
1, and an FKM/KNO.sub.3 composition was obtained. The FKM/KNO.sub.3
composition obtained was ground on a cutter type grinding mill
(Rapid R1528, product of KAWATA MFG Co.) to give a roughly ground
FKM-based composition with an average particle diameter of 1 to 3
mm. The roughly ground FKM-based composition was further ground on
a disk type pulverizer to give an FKM-based powder composition with
an average particle diameter of 500 .mu.m. A polymer processing
additive was prepared by covering 100 parts of the FKM powder with
10 parts of talc.
[0138] A masterbatch of the polymer processing additive was
prepared in the same manner as in Example 1 except for the above
procedure, and subjected to extrudability evaluation. At about 6
minutes after the start of feeding of the molding composition, the
extrusion pressure began to drop and the incidence of melt fracture
began to decrease. At 15 minutes after the start of the above
feeding, no more melt fracture was found at all and the extrusion
pressure dropped from 38.2 MPa to 35.6 MPa.
[0139] The extrusion pressure and melt fracture incidence
measurement results are shown in Table 1.
[0140] The fluoroelastomer in the masterbatch of the polymer
processing additive was found dispersed as particles with an
average particle diameter of about 1 .mu.m.
Example 3
[0141] The same FKM crumbs as used in Example 1 were transferred,
without addition of the aqueous solution of KNO.sub.3, to the
extruder and dried. This FKM was ground on a cutter type grinding
mill (Rapid R1528, product of Kawata Mfg Co.) to give roughly
ground FKM with an average particle diameter of 1 to 3 mm. A 50-g
portion of this roughly ground FKM and a solution of 0.025 g of
KNO.sub.3 in 2 ml of pure water were placed in a glass container
(container attached to the mixer mentioned below), which was
mounted on a mixer (MILLSER IFN-300DG; product of IWATANI); the
mixture was blended up in the glass container at ordinary
temperature (23.degree. C.) for 1 minute, whereby an FKM/KNO.sub.3
composition was obtained.
[0142] A 40-g portion of the thus-obtained KNO.sub.3-treated FKM
was covered with 4 g of talc, and the whole was blended with 1956 g
of LDPE (LDPE SUMIKATHENE G201, MFR=2, product of SUMITOMO
POLYETHYLENE) by tumbling so that the FKM content might amount to
2% by mass. The resulting mixture was fed to a twin-screw extruder
(2D-25S, product of TOYO SEIKI) with high-shear screws incorporated
therein to give a masterbatch of the polymer processing
additive.
(Extrusion Conditions)
[0143] (1) Temperatures: 170 to 200.degree. C., die temperature
200.degree. C. (2) Number of screw rotations: 100 rpm
(3) L/D: 25
[0144] A molding composition was prepared by weighing an amount of
the masterbatch of the polymer processing additive obtained
sufficient to give an FKM content of 500 ppm in the composition and
incorporating the same into metallocene LLDPE (product name: Evolue
SP2520, product of Prime Polymer Co.), and the molding composition
was fed to the hopper of the above-mentioned extruder for
extrudability evaluation in the same manner as in Example 1.
[0145] The observation of changes in extrusion pressure was started
just after the feeding of the above molding composition. The
extrusion pressure at the start of feeding was 38.4 MPa. In about
10 minutes after the start of feeding, the extrusion pressure began
to drop and, at 16 minutes after the start of feeding, dropped to
37.3 MPa; from this point of time to 30 minutes after the start of
feeding, the extrusion pressure changed little. The incidence of
melt fracture decreased but the condition was such that melt
fracture had not yet disappeared completely; therefore, at 30
minutes after the start of feeding, the masterbatch of the polymer
processing additive was weighed and fed so that the FKM after
admixture might amount to 750 ppm. At 21 minutes after the
additional feeding (51 minutes after the initial feeding), the
complete disappearance of melt fracture was observed and the
extrusion pressure dropped to 36.5 MPa.
Example 4
[0146] The fluoroelastomer used in Example 2 was ground on a cutter
type grinding mill (Rapid R1528, product of Kawata Mfg Co.) to give
roughly ground FKM with an average particle diameter of 1 to 3 mm.
A 50-g portion of this roughly ground FKM and a solution of 0.025 g
of KNO.sub.3 in 2 ml of pure water were placed in a glass container
(container attached to the mixer mentioned below), which was
mounted on a mixer (MILLSER IFN-300DG; product of IWATANI); the
mixture was blended up in the glass container for 1 minute, whereby
an FKM/KNO.sub.3 composition was obtained.
[0147] The thus-obtained KNO.sub.3-treated FKM was placed in a
mixer (R-60; product of TOYO SEIKI) and kneaded at 170.degree. C.
for 10 minutes. The thus-obtained FKM/KNO.sub.3 composition (added
KNO.sub.3 concentration: 500 ppm) was again ground on the cutter
type grinding mill to give a finely divided FKM-based
composition.
[0148] Using the finely divided FKM-based composition, a
masterbatch of the polymer processing additive was prepared in the
same manner as in the case of the KNO.sub.3-treated FKM in Example
3.
[0149] The masterbatch of the polymer processing additive obtained
was subjected to blown film extrudability evaluation in the same
manner as in Example 1.
[0150] Just after feeding, the extrusion pressure was 38.0 MPa; in
15 minutes after feeding, melt fracture completely disappeared and
the extrusion pressure dropped to 35.2 MPa.
Example 5
[0151] The procedure for extrudability evaluation of Example 4 was
followed in the same manner except that KNO.sub.3 was added in an
amount corresponding to 100 ppm of FKM. Melt fracture once
disappeared in 15 minutes after feeding but again appeared at 20
minutes after feeding and completely disappeared at 30 minutes
after feeding. The extrusion pressure dropped from 38.0 MPa to 35.6
MPa.
Example 6
[0152] The procedure for extrudability evaluation of Example 4 was
started in the same manner except that KNO.sub.3 was added in an
amount corresponding to 1000 ppm of FKM. When the content of FKM in
the molding composition was 500 ppm, melt fracture did not
disappear completely even after the lapse of 30 minutes and, when
the amount of FKM was increased to 750 ppm and the evaluation
procedure was continued, melt fracture completely disappeared in 28
minutes (after a total extrusion time of 58 minutes). The extrusion
pressure lowered from 37.9 MPa to 36.4 MPa when the content of FKM
in the molding composition was 500 ppm and, when the amount of FKM
was increased to 750 ppm, it lowered to 36.0 MPa.
Example 7
[0153] A masterbatch of the polymer processing additive was
prepared and extrudability evaluation was made in the same manner
as in. Example 4 except that NaNo.sub.3 was used in lieu of
KNO.sub.3.
[0154] When the FKM content in the molding composition was 500 ppm,
melt fracture did not disappear completely even after 30 minutes;
when the FKM content was increased to 750 ppm and the evaluation
was continued, melt fracture disappeared completely in 19 minutes
(after a total extrusion time of 49 minutes). When the FKM content
was 500 ppm, the extrusion pressure decreased from 37.4 MPa to 36.3
MPa and, when the FKM content was increased to 750 ppm, it dropped
to 35.5 MPa.
Example 8
[0155] A masterbatch of the polymer processing additive was
prepared and extrudability evaluation was performed in the same
manner as in Example 4 except that K.sub.2CO.sub.3 was used in lieu
of KNO.sub.3.
[0156] When the FKM content in the molding composition was 500 ppm,
melt fracture did not disappear completely even after 30 minutes;
when the FKM content was increased to 750 ppm and the evaluation
was continued, melt fracture disappeared completely in 30 minutes
(after a total extrusion time of 60 minutes). When the FKM content
was 500 ppm, the extrusion pressure decreased from 36.9 MPa to 36.0
MPa and, when the FKM content was increased to 750 ppm, it dropped
to 35.9 MPa.
Example 9
[0157] A masterbatch of the polymer processing additive was
prepared and extrudability evaluation was performed in the same
manner as in Example 4 except that Mg(NO.sub.3).sub.2 was used in
lieu of KNO.sub.3.
[0158] When the FKM content in the molding composition was 500 ppm,
melt fracture did not disappear completely even after 30 minutes;
when the FKM content was increased to 750 ppm and the evaluation
was continued, melt fracture disappeared completely in 24 minutes
(after a total extrusion time of 54 minutes). When the FKM content
was 500 ppm, the extrusion pressure decreased from 37.1 MPa to 36.0
MPa and, when the FKM content was increased to 750 ppm, it dropped
to 35.4 MPa.
Comparative Example 1
[0159] A masterbatch of the polymer processing additive was
prepared in the same manner as in Example 1 except that the drying
by extrusion was carried out without addition of KNO.sub.3.
[0160] The fluoroelastomer in the masterbatch of the polymer
processing additive obtained was found dispersed as particles with
an average particle diameter of about 1 to 7 .mu.m (cf. FIG.
4).
[0161] Using the above masterbatch of the polymer processing
additive, the same extrusion procedure as in Example 1 was carried
out.
[0162] From the point of time after the lapse of about 10 minutes
following the start of feeding of the molding composition, the
extrusion pressure began to decrease and the incidence of melt
fracture began to lower. However, even after the lapse of 30
minutes following the start of feeding, melt fracture did not
disappear and the extrusion pressure decreased from 38.3 MPa only
to 37.0 MPa.
[0163] Since the condition was such that the incidence of melt
fracture decreased but melt fracture did not disappear completely,
the above masterbatch of the polymer processing additive was
weighed in an amount sufficient for the FKM content after mixing to
correspond to 1000 ppm and additionally fed at the time after the
lapse of 35 minutes following the start of feeding of the molding
composition. In 10 minutes after the additional feeding (at 50
minutes after the start of the initial feeding), complete
disappearance of melt fracture could be confirmed and the extrusion
pressure lowered to 36.3 MPa. The melt fracture measurement results
are shown in FIG. 2.
[0164] It was found that the molding composition of Example 1 which
contained the polymer processing additive heat-treated with
KNO.sub.3 added could lower the extrusion pressure to about 36 MPa
at an addition level about half as compared with the molding
composition of Comparative Example 1 which contained the polymer
processing additive obtained without such heat treatment.
Comparative Example 2
[0165] A masterbatch of the polymer processing additive was
prepared in the same manner as in Example 2 except that the drying
and grinding were carried out without adding KNO.sub.3.
[0166] The fluoroelastomer in the masterbatch of the polymer
processing additive obtained was found dispersed as particles with
an average particle diameter of about 1 to 4 .mu.m (FIG. 5).
[0167] Using the above masterbatch of the polymer processing
additive, the same extrusion procedure as in Example 1 was carried
out.
[0168] From the point of time after about 10 minutes following the
start of feeding of the molding composition, the extrusion pressure
began to lower and the incidence of melt fracture began to
decrease. However, even after the lapse of 30 minutes following the
start of the above feeding, melt fracture did not disappear; the
extrusion pressure lowered from 38.3 MPa only to 37.3 MPa.
[0169] Further, it was found that whereas the molding composition
of Example 2 which contained the polymer processing additive
heat-treated with KNO.sub.3 added could cause melt fracture to
completely disappear in about 15 to 20 minutes after the start of
feeding, an incidence of about 37% of melt fracture remained even
after the lapse of 1 hour with the molding composition of
Comparative Example 2 which contained the polymer processing
additive obtained without such heat treatment.
Comparative Example 3
[0170] A masterbatch of the polymer processing additive was
prepared in the same manner as in Example 3 except that the
KNO.sub.3 treatment was omitted.
[0171] Using the masterbatch of the polymer processing additive
obtained, the same extrusion procedure as in Example 1 was carried
out.
[0172] At about 10 minutes after the start of feeding of the
molding composition, the extrusion pressure began to lower and the
incidence of melt fracture began to decrease. However, even after
the lapse of 30 minutes following the start of feeding, melt
fracture did not disappear; the extrusion pressure lowered from
38.2 MPa only to 37.4 MPa. Therefore, at the point of time after
the lapse of 30 minutes following the start of feeding, the
masterbatch of the polymer processing additive was weighed in an
amount sufficient for the FKM to amount to 750 ppm of the molding
composition after mixing and additionally fed, as in Example 3.
Even at 30 minutes after the additional feeding (60 minutes after
the start of feeding), melt fracture did not disappear completely;
the extrusion pressure lowered only to 37.2 MPa.
Comparative Example 4
KNO.sub.3-Coated G701BP Masterbatch
[0173] The masterbatch of the polymer processing additive prepared
in Comparative Example 1 was sprayed with a 20% aqueous solution of
KNO.sub.3 so that the amount of KNO.sub.3 might correspond to 500
ppm of the amount of FKM. After tumbling, the whole was dried at
100.degree. C. for 1 hour. Using the thus-obtained KNO.sub.3-coated
G701BP masterbatch of the polymer processing additive, the same
blown film extrusion as in Example 1 was carried out.
[0174] From the point of time about 10 minutes after the start of
feeding of the molding composition, the extrusion pressure began to
lower and the incidence of melt fracture began to decrease.
However, even after the lapse of 60 minutes following the start of
the feeding, melt fracture did not disappear; the extrusion
pressure lowered from 38.3 MPa only to 37.3 MPa.
[0175] The measurement results in each comparative example, and
each example are shown in Table 1 and Table 2, respectively.
TABLE-US-00001 TABLE 1 Compar. Ex. 1 Compar. Ex. 2 Compar. Ex. 3
Compar. Ex. 4 Polymer Amount of specific None None None 500
processing metal inorganic salt additive (based on amount of FKM)
(ppm) Method of mixing As in Example 1 As in Example 2 As in
Example 3 Spraying MB with KNO.sub.3 Molding Amount of FKM 500
.fwdarw.1000 500 500 .fwdarw.750 500 composition (based on molding
composition) (ppm) Melt fracture 30 10 30 30 30 30 disappearance
(Did not (Did not (Did not (Did not (Did not (min) disappear)
disappear) disappear) disappear) disappear) Extrusion pressure
(MPa) 38.3.fwdarw.37.0 .fwdarw.36.3 38.3.fwdarw.37.3
38.2.fwdarw.37.4 .fwdarw.37.2 38.3.fwdarw.37.3
TABLE-US-00002 TABLE 2 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 Polymer Amount of KNO.sub.3 400 KNO.sub.3 250
KNO.sub.3 500 KNO.sub.3 500 KNO.sub.3 100 KNO.sub.3 1000 processing
specific metal additive inorganic salt (based on amount of FKM)
(ppm) Method of Drying by Drying by Spraying.fwdarw.MB
Mixer.fwdarw.MB Mixer.fwdarw.MB Mixer.fwdarw.MB mixing extrusion
extrusion Molding Amount of 500 500 500 .fwdarw.750 500 500 500 750
composition FKM (based on molding composition) (ppm) Melt fracture
20 15 30 21 15 15.fwdarw.20 30 28 disappearance (Did not
(Reappeared) (Did not (min) disappear) .fwdarw.30 disappear)
(Disappeared) Extrusion pressure (MPa) 38.0.fwdarw.36.0
38.2.fwdarw.35.6 38.4.fwdarw.37.3 .fwdarw.36.5 38.0.fwdarw.35.2
38.0.fwdarw.35.6 37.9.fwdarw.36.4 .fwdarw.36.0 Example 7 Example 8
Example 9 Polymer Amount of NaNO.sub.3 500 K.sub.2CO.sub.3 500
Mg(NO.sub.3).sub.2 500 processing specific metal additive inorganic
salt (based on amount of FKM) (ppm) Method of Mixer.fwdarw.MB
Mixer.fwdarw.MB Mixer.fwdarw.MB mixing Molding Amount of 500
.fwdarw.750 500 .fwdarw.750 500 .fwdarw.750 composition FKM (based
on molding composition) (ppm) Melt fracture 30 19 30 30 30 24
disappearance (Did not (Did not (Did not (min) disappear)
disappear) disappear) Extrusion pressure (MPa) 37.4.fwdarw.36.3
.fwdarw.35.5 36.9.fwdarw.36.0 .fwdarw.35.9 37.1.fwdarw.36.0
.fwdarw.35.4
INDUSTRIAL APPLICABILITY
[0176] The polymer processing additive and the masterbatch of the
polymer processing additive of the invention, which have the
respective constitutions described hereinabove, are higher in
moldability-improving effects, for example in reducing the
extrusion pressure and inhibiting melt fracture, than the prior art
ones. The molding composition of the invention, which comprises the
above-mentioned polymer processing additive, is excellent in
moldability, and the molded article of the invention, which is the
product of molding of the above molding composition, is excellent
in mechanical properties and other dynamic properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0177] FIG. 1 This is a photomicrograph taken under an optical
microscope and showing the state of dispersion of the polymer
processing additive in the masterbatch of the polymer processing
additive in Example 1.
[0178] FIG. 2 This shows the results of melt fracture measurement
in Example 1 and Comparative Example 1.
[0179] FIG. 3 This is a photomicrograph taken under an optical
microscope and showing the state of dispersion of the polymer
processing additive in the masterbatch of the polymer processing
additive in Example 2.
[0180] FIG. 4 This is a photomicrograph taken under an optical
microscope and showing the state of dispersion of the polymer
processing additive in the masterbatch of the polymer processing
additive in Comparative Example 1.
[0181] FIG. 5 This is a photomicrograph taken under an optical
microscope and showing the state of dispersion of the polymer
processing additive in the masterbatch of the polymer processing
additive in Comparative Example 2.
* * * * *